Hitherto, a document created by a person was stored only in a private personal computer (PC), but at present, a file sharing system is used in which the document can be mutually used among persons belonging to the same department or performing the same work. Although the file sharing system is often realized as a basic function of an operating system (OS) such as, for example, Windows (trade mark of Microsoft Corp.), it is often implemented as a groupware system in which work environment in the office is integrated by combing communication tools such as mail, bulletin board system, and schedule management. Incidentally, here, a document file will be considered as a file.
In the document file sharing system, it can be said that not only documents can be mutually referred to among collaborative workers, but also mutual communication is realized through the documents. As means for communication, face-to-face conversation or telephone has highest real-time characteristics, and communication through the mail or documents has low real-time characteristics. However, the communication through the mail or documents has a merit that the same information can be transferred to many persons at once, and as the Internet becomes common, the chance of its use is increased.
The communication through documents starts from a point where ideas are collected into a document. The created document is stored in a document sharing system, and is made open to other users. Then, a collaborative worker reads the document, creates another document or updates the document, and stores it again in the document sharing system. By repeating this operation, the communication through the document is realized. In this communication, there is a feature that ideas of many persons are more easily reflected than creation of the document by one person, more ideas are packed, and the document with less error by mutual check is created. In this meaning, the merit by the collaborative work can be sufficiently utilized.
A problem of this communication is that a collaborative worker does not readily notice that the document is open to the public. Although the problem is resolved when it is notified to participants by mail or the like that the information has been registered or updated, this is not welcomed, because mails to be received are increasing in recent years. The user cannot deal with many mails and there is a possibility that he or she fails to read such a mail. Besides, because a sender restricts the range of notification, there is a problem that a person's potential chance of newly entering the communication is lost.
On the other hand, when persons are in the same office, it is possible to know, to some extent, who is interested in what and is in what work state now. This is due to informal communication made in the interim of the work. When persons are close to each other, the chance of coming in contact with each other, in addition to the work, is increased, and the conversation about topics other than the work is increased. When a person is usually exposed to such information, he or she notices that the information created by other collaborative workers can be utilized, and there occurs a chance that the information being shared is secondarily used. However, the environment in which the informal communication can be performed does not always exist.
As related art in this field, there is an instant message service in the Internet. Although various application programs for instant messages are used, the application program has a function to indicate whether another user is connected to the network, and the state of the user, for example, he or she is on the job or on a break. Besides, it is proposed to provide notification of the state of not only a person but also an object.
US2002-169826 discloses a system of providing notification of the state of a document such as update. JP-A-7-234843 discloses an example of a case where a document is used jointly. In this publication, when a collaborative work is performed through a shared document, there is adopted such a contrivance that the history of the collaborative work can be held in a place different from a storage area for the document. According to the system of this publication, as long as the place where an objective document is held is known, the state of the work relating to the document can be grasped.
As stated above, in the conventional document sharing system, the registered document can be merely referenced from the collaborative worker, and there is no contrivance to provide notification of the existence of the information. Besides, a relation between users through documents does not become clear.